Sizing Boiler and Pipes for Radiant Heat Flooring
Potton| Posted inMechanicalson
Once I have calculated the thermal losses for all my rooms, how do I translate that into the requirement for a hydronic system components (electric boiler power, spacing of pipes, etc.) …?
[Single floor house, slab on ground, cathedral ceiling, in zone 6]
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The heat loss should show something like 20,000 btu per hour. This needs to be balanced with your heat emitters which could in PEX in concrete, placed 2 inches below the surface and 9 to 12 inches apart. Check sources but I think that is 12 to 15 BTU per square foot. Limit the length of your PEX runs to no more than 300 ft. Move from the outer walls to the inside. Check out LoopCAD, and John siegenthalers hydronic design books Then select a heat pump or boiler that can produce the load. Some heat pumps also do cooling, so you may want to add a hydronic run or two for cooling purposes. Size in your DWH system which may require an additional 10,000 btu per hour. Guidelines are to run the water at no more than 110F to 120F, in zone 6 I run my water below 103f, so a simple water heater meets the requirements.
Check out these articles:
How to Perform a Heat-Loss Calculation — Part 1
How to Perform a Heat-Loss Calculation — Part 2
Who Can Perform My Load Calculations?
This is a subject that whole books have been written about. It would help if you did a little research and then broke it up into a bunch of smaller questions.
> electric boiler power
+1 on using a heat pump. Where the lower temperatures do effect piping and radiators.
When you use electricity matters (to the environment if not your pocketbook) - so at least look at adding thermal storage.
Consider hiring someone experienced to do the design.